Abstract
The activity of the purified poly (U) polymerase replication complex of foot-and-mouth disease virus was optimized when 100mM NH4+ and either 0.75mM Al3+ or 1.0mM Fe3+ was added to the standard assay reaction mixture. Zn2+ at concentrations of 10−5 mM to 5mM inhibited enzyme activity although all polymerases examined to date have contained zinc. Mercaptoethanol and dithiothreitol inhibited polymerase activity despite the presence of cysteine residues in the viral induced polypeptide of the replication complex, possibly because of their action as metal chelators rather than as reducing agents.